I stood outside the closed door of the hospital room where an adorable 6-week-old baby lay all alone in her crib. As I scrubbed my hands in the sink outside the isolation room, an electronic monitor allowed me to hear her breathing peacefully.

Suddenly the quiet was shattered by a fit of coughing. And she couldn't stop. The coughs came so closely together that she couldn't catch her breath. I grabbed a mask from above the sink and, pressing it over my face, entered her room. The coughing continued. The pulse and oxygen monitor at her bedside complained insistently that her blood-oxygen levels were dropping too. The EKG monitor sounded an alarm that her heart rate was dropping. And she continued to cough. Even before I reached her bedside I could see that her face was turning blue. She began to vomit.

Moments later the peace had returned. Her various monitors beeped tranquilly; the coughing spasm was over. This little girl with pertussis survived, but she had many more weeks of coughing spasms before she could return home to her parents.

Pertussis, or whooping cough, which once ravaged children around the world, is again on the rise. Worldwide, about 300,000 people die from pertussis each year. Global travel can result in outbreaks anywhere. Earlier this month, all pediatricians in my area received a public health alert about a sudden, dangerous increase in pertussis cases.

On the other end of the pertussis spectrum, I saw a healthy 12-year-old boy in my office this week. He had had a nagging cough for the last month. Sometimes he hacked up mucus with his cough. Sometimes the cough came in fits. Once or twice he had coughed until he vomited. Otherwise he felt pretty well -- he just couldn't seem to shake the cough.

Pertussis is caused by bacteria that attach themselves to the cilia (little hairs) that line the respiratory tract. These bacteria produce a potent toxin that inflames the respiratory tract and that prevents the cilia from functioning properly. The disease can be serious or fatal in infants and unimmunized children. It is much milder in teens, adults, and in immunized children - but still can be a real nuisance. As you might guess, it can be far worse in people with asthma or with immune deficiencies.

People with pertussis go through four stages:

1. Incubation. For 5 to 21 days after exposure (usually 7 to 10 days) there are no symptoms at all while the bacteria multiply.
2. Prodrome. For the next 1 to 2 weeks, pertussis is not unlike a cold. People have runny noses, sneezing, and perhaps a low-grade fever. A mild cough begins that gradually worsens.
3. Paroxysms. The worst part of the illness lasts from 1 to 6 weeks. Spasms or attacks of coughing may come up to 15 times per day. Sometimes, especially in children, the cough is followed by a "whoop" noise as they breathe in rapidly, attempting to get air. Even so, young infants will often turn blue with the spells from lack of oxygen. The mucus is often thick and sticky. Gagging, choking, and vomiting are common. Sometimes young infants will stop breathing for varying lengths of time. This stage of pertussis is much milder in adults, teens, older children, and immunized children.
4. Convalescence. As if this disease were not already long enough, the cough continues for another 2 to 4 weeks, but gradually becomes less severe and less frequent. Even after the cough seems finally over, the spasms often recur briefly for the next several months - especially during colds and during exertion.

Current lab tests to detect pertussis are either slow, cumbersome, not readily available, or often fail to pick up the disease. For this reason many physicians rely on the working definition of pertussis. Also for this reason, the number of proven cases reported to the health department vastly underestimates the number of cases in the community.

According to the Centers for Disease Control and Prevention people are considered to have pertussis if they have a cough lasting for at least 14 days (with no other confirmed cause) and any one of the following symptoms (even if they have been immunized):

• Coughing spasms or fits (coughs comes in clusters)
• A whooping noise while breathing in.
• Vomiting caused by the cough.

The case is called confirmed pertussis if there is a positive lab test or if there has been exposure to someone with a positive lab test.

During a pertussis outbreak, anyone who has a cough lasting at least 14 days (with no other known cause) probably has pertussis, even in the absence of other specific symptoms.

Pertussis is treated with an antibiotic (Biaxin, erythromycin, Septra, or Zithromax). The antibiotic doesn't much affect the length of the illness, but is very effective at stopping its spread. People with pertussis are highly contagious for up to 5 days after starting the antibiotic.

You or your child have been exposed if you spend a total of 5 hours in the same room with someone with the disease (over a week), or if you sit next to someone with pertussis for any length of time, or if you have any contact at all with infected mucus or saliva. Between 70 and 100 percent of susceptible people will catch pertussis if they are exposed.

Currently, most adults and teens are susceptible because the protective effect of their childhood pertussis immunizations has waned. To address this problem, it is now recommended that all teens receive a booster vaccine at 11-18 years of age (preferably between 11-12 years).

Between 60 and 80 percent of infants are protected after the first 3 doses of vaccine, but this protection begins to disappear when they are toddlers. After the 4th immunization at 18 months old, 80 percent are protected for the next 3 to 4 years. The 5th dose, at kindergarten entry, protects them for another few years. A booster dose is recommended during the teen years to bolster immunity to pertussis.

People who have been exposed to probable or confirmed pertussis should either receive a course of preventative antibiotics (and I say this as someone strongly opposed to the overuse of antibiotics), or be kept home from daycare, school, or work for at least 3 weeks. If the exposed individual develops symptoms, they should receive antibiotics to prevent further spread of pertussis to others.

Children under age 7 who have been exposed should receive a pertussis vaccine, unless they have already had 4 doses of pertussis vaccine (and the last dose within 3 years), or unless there is a compelling reason not to immunize them. Exposed teens 11-18 years old who have not already received a booster vaccine should receive one.

Your children, Maureen, are beyond the age of greatest risk from the illness. Even so, they would likely benefit from getting the vaccine now. Their previous reactions to the vaccine fall into the mild or moderate category. Please discuss their unique situations with their doctor to help you reach a decision. You will be glad to know that the pertussis vaccine used today is gentler and safer than that used 5 years ago.

On other fronts, vaccines have eliminated the dreaded smallpox from around the globe. In all likelihood, paralytic polio will also have been eliminated within the next few years.

The pertussis vaccine, even with its side effects and problems, has saved many lives by stopping the wildfire spread of pertussis epidemics. The recent pertussis deaths in California, though, are a haunting reminder that this disease is still lying in wait.